Is this a known game, or just something I invented?
In carom 8-ball, the only time that the tip of your cue comes in contact with the white cue ball is on the break. The object of the game is to sink the ball that you are hitting with your cue, in the pocket that you call. It's as if you were trying to scratch on every shot. You can't simply shoot your ball directly into a pocket, it has to carom off any other ball. If it doesn't carom off another ball then it will get spotted and it's loss of turn. Again, the only legal shot is when the ball that you hit with your cue stick falls in the pocket that you call after it makes contact with another ball.
The rules for the order that balls are pocketed, including open table and choice of solids or stripes, are the same as in 8-ball. Sinking the 8-ball after making your other seven balls wins the game. If the player shooting makes a legal shot and also pockets another ball, then that ball will stay down. If the shooting player fails to make a legal shot but slops another ball in, his ball will be spotted while his opponent's ball will stay down. The white ball must be on the table for every shot, if it falls in then it will be spotted before the next shot. Calling the cue ball in the corner pocket on the break is a legal shot, this allows the player to shoot again after spotting the white ball. The need for the white ball to remain on the table is evident when both players are shooting at the 8-ball, they need another ball to carom off of.
The reason I invented this game was for practice at caroms. In 9-ball, situations arose where I had an option to carom off of the lowest ball to sink the 9. In 8-ball, there were situations where a pocket was blocked by an opponents ball and I needed to first short rail my ball then carom off his to pocket my ball. It also helped with getting a better feel for tangent lines and Q-ball control.
I haven't played this game in years, but I believe it taught me some valuable lessons.
A friend of mine once ran a rack in five shots, not counting the break, making two of his balls at a time. I was very impressed.